Currently, display modes of Thin Film Transistor-Liquid Crystal Displays (TFT-LCDs) may be divided into a Twisted Nematic (TN) mode, an In Plane Switching (IPS) mode, an Advanced Super Dimension Switch (ADS) mode, a Vertical Alignment (VA) mode, etc. In the wide viewing angle display technique, the VA mode has a greater viewing angle performance than the TN mode, and further has characteristics such as excellent reaction time and high contrast etc. As a result, the VA mode is widely applied in wide viewing angle liquid crystal display panels.
A VA mode display panel comprises a plurality of pixel units, each of which corresponds to a minimum display point which may be independently controlled on a display screen. Liquid crystal molecules may change from being arranged vertically (i.e., in a direction perpendicular to a surface of the display panel) to being inclined in a specific direction under the control of a driving voltage. As a light filtering capacity of a liquid crystal layer is determined by an angle between liquid crystal molecules and light, if liquid crystal molecules in a certain pixel unit are aligned in the same direction, brightness of the pixel unit appears to be different at different positions, and thus there is a color washout problem at a large viewing angle in the VA mode. In order to solve the color washout problem, there is proposed a multi-domain technique in the related art. The multi-domain technique is to divide each pixel unit into a plurality of domains, wherein liquid crystal molecules in each of the domains are aligned in the same direction and liquid crystal molecules in different domains are aligned in different directions (in different alignments and/or at angles of inclination). Due to the average of the domains, a brightness difference of the pixel unit at different viewing angles can be reduced. There are two classes of methods to divide the pixel unit into domains. One class of methods is to change alignment of the liquid crystal molecules (that is, set multiple alignment domains). It can be realized by setting bumps or different alignment layers, or by changing a shape of the pixel electrode, etc. The other class of methods is to provide a plurality of sub-pixel electrodes having different voltages in each pixel unit (i.e., the plurality of sub-pixel electrodes are commonly used to display content of one pixel), so that liquid crystal molecules corresponding to the different sub-pixel electrodes are aligned differently. Of course, the two classes of methods may be used in combination. That is, each pixel unit has multiple sub-pixel electrodes, and each sub-pixel electrode then corresponds to a plurality of alignment domains.
Currently, with regard to a pixel unit which may be divided into a number of (for example, 8) domains, there are proposed techniques such as capacitive coupling, charge sharing, or 2D1G/2G1D etc. in the related art. The inventor of the present application has found that the techniques in the related art have problems such as complex structure, low aperture ratio and increased cost etc. For example, in the 2D1G/2G1D technique, two signal lines are used to input signals. In this case, not only a number of the signal lines is doubled, but also a number of conversion chips such as Chip on Flexes (COFs) connected to the signal lines is doubled, resulting in an increased cost of a panel. As another example, in the capacitive coupling and charge sharing techniques, three thin film transistors and corresponding capacitors are required in each pixel unit, which results in a complex structure and a low aperture rate.